#define  _CRT_SECURE_NO_WARNINGS
#include<stdio.h>

int Fib(int n)
{
	if (n == 1 || n == 2)
	{
		return 1;
	}
	else
	{
		return Fib(n - 1) + Fib(n - 2);
	}
}

int main()
{
	int n = 0;
	while (scanf("%d", &n) != EOF)
	{
		int r = Fib(n);
		printf("%d", r);
	}
	return 0;
}